1. Field of the Invention
The present invention concerns an improvement for a structure of a connector for connecting metal or synthetic resin tubes of a relatively small diameter of less than about 20 mm, which are often disposed and used as a pipe-line for supplying oils and gases generally in automobiles or various kinds of machineries and equipments (hereinafter simply referred to as a pipe).
2. Description of the Prior Art
The connector of the aforementioned type has been constituted so far, for example, as shown in FIG. 23 such that a receptacle member 22 having a pair of resilient finger walls 23 which are situated at a portion forward in the inserting direction of circumferential wall of around a through hole at the axial center of a connector main body 21 and protruded being inclined forward is engaged to a stepped portion 24 of a connector main body disposed to the rear annular circumferential wall 23' at an engaging wall 21 in the rear portion of the connector main body 21 and, in this state, a pipe P.sub.0 is connected by engaging the finger wall 23 to an annular bulged wall P.sub.0 ' of the incorporated pipe P.sub.0.
Further, a connector in Japanese Patent Publication Sho 64-10711, is constituted such that a retaining element is inserted into the housing (connector main body), a jaw end of the retainer element is urged to expand outward by the annular surface of a pipe as it is inserted thereby enabling the insertion of the pipe and, when the jaw end passes over the annular surface, the Jaw end returns to its inward home position and abuts against the engaging wall of the pipe to prevent it from slipping off.
Furthermore, a connector as shown, for example, in Japanese Utility Model Laid-Open Hei 1-136791 has such a constitution that incorporating at the inside of a connector main body upon pipe connection is visually observed reliably by the deformation of a sensing finger incorporated in the connector main body as an observation means.
However, in the prior art shown in FIG. 23, since the connector is engaged to the annular bulged wall P.sub.0 ' due to the snapping function of the finger wall 23 in the connection state of the pipe P.sub.0, the engagement between them is somewhat unreliable. Then, when tension is exerted on the pipe P.sub.0 due to the fatigue for long period of time of the finger wall 23, the top end of the finger wall is expanded to cause disengagement, thereby making the connection instable and tending to induce undesirable leakage.
Further, in the pipe connector as described in Japanese Patent Publication Sho 64-10711, since it is necessary that the diameter of the retainer is larger as compared with that of the pipe in order to obtain a snapping action of a resilient finger of the retainer upon inserting the pipe and the length of the retainer is also increased, the size of the connector main body is made larger which is not suitable to disposition in a narrow space. Further, since the clipping lug end for detaching the pipe is protruded, it involves such a problem that the pipe may be detached accidentally due to interference with other parts, etc.
Furthermore, in the prior art as described in Japanese Patent Utility Model Laid-Open Hei 1-136791, since the sensing finger is small, it is difficult to confirm connection in a narrow or dark place. In addition, since the sensing finger deforms to some extent even if the locked state is insufficient and it leads to a problem of erroneously recognizing this as complete locking.